4/5/2012 2:22 AM PDT

A "spoon with a white crystal-like substance on it" and a "white powdery substance" -- which we know was later tested and determined to be cocaine -- was found in the hotel room where Whitney Houston died ... this according to the singer's final autopsy report.

The report, which gives a detailed description of Whitney's room when officials arrived, says "Located on the south portion of the counter was a small spoon with a white crystal-like substance in it and a rolled up piece of white paper, along with other miscellaneous items."

"Located in the top drawer, in the north side of the counter were remnants of a white powdery substance, and a portable mirror on a base." Officials found more white powder on the base of the mirror.

The report also states, "[Whitney] possibly overdosed on a narcotic substance, prescription medications, over the counter medications and alcohol."

According to the report, Whitney's body was discovered FACE DOWN in the bath tub ... with a "bloody purge coming from her nose." Officials say there were no signs of foul play.

The report notes Whitney had a history of substance abuse ... which was evident by a "perforation of posterior nasal septum."

The singer's official cause of death is listed as accidental drowning -- but heart disease and "chronic" cocaine use were contributing factors.

The report notes ... when officials discovered the body, Whitney was wearing a brown wig "tightly attached to the hair."

As TMZ previously reported, Whitney had cocaine in her system at the time of her death -- which tests showed she used immediately prior to her death.

Officials say Houston also had traces of marijuana in her system ... as well as Xanax (anxiety medication), Flexeril (muscle relaxer) and Benadryl (allergy medication).

As we previously reported, Whitney was found dead in a bathtub on Feb.11 at the Beverly Hilton hotel.